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Tyler Rinker

2011-Jul-30 05:48 UTC

[R] ifelse returns

Greetings R Community,
 
I am working with the ifelse function and it is returning something unexpected. 
In the code the line with the MODE1 assignment the output is a vector [1] 4 5 6 
but when I put the MODE1 object into the ifelse function [R}'s output for
MODE1 is the first number from the string (4).  Why is this?  Given the supplied
vector of x I would assume both the MODE1 and ifelse() lines to return the same
result.  I would like the ifelse to return the entire vector [1] 4 5 6 as in the
previous line.
 
OS: Win7
R version 2.14 beta


#======================================================================#        
Beginning of code
#======================================================================x<-c(2,3,4,4,5,5,6,6,8,10)
  
df<-as.data.frame(table(x))       
df<-df[order(df$Freq),]         
m<-max(df$Freq)        
(MODE1<-as.vector(as.numeric(as.character(subset(df,Freq==m)[,1]))))
ifelse(sum(df$Freq)/length(df$Freq)==1,warning("No Mode: Frequency of all
values is 1", call. = FALSE),MODE1)
#======================================================================#        
End of code
#====================================================================== 
                                                R Console
Output> (MODE1<-as.vector(as.numeric(as.character(subset(df,Freq==m)[,1]))))
[1] 4 5 6> ifelse(sum(df$Freq)/length(df$Freq)==1,warning("No Mode: Frequency of
all values is 1", call. = FALSE),MODE1)[1] 4
 
Thank you in advance,
Tyler 		 	   		  
	[[alternative HTML version deleted]]

jim holtman

2011-Jul-30 05:59 UTC

head link

[R] ifelse returns

You might want to breakdown some of the expressions you are using; for example:
> x<-c(2,3,4,4,5,5,6,6,8,10)
>
> df<-as.data.frame(table(x))
> df<-df[order(df$Freq),]
> m<-max(df$Freq)
> (MODE1<-as.vector(as.numeric(as.character(subset(df,Freq==m)[,1]))))
[1] 4 5 6> ifelse(sum(df$Freq)/length(df$Freq)==1+     ,warning("No Mode: Frequency of all values is 1", call. = FALSE)
+     ,MODE1)
[1] 4>
> sum(df$Freq)/length(df$Freq)==1
[1] FALSE>  sum(df$Freq)/length(df$Freq)
[1] 1.428571>
notice that 'sum(df$Freq)/length(df$Freq)' only returns a single value
and the expression in the 'ifelse' evaluates to FALSE, so only the
first value of MODE1 is returned.

So when you get unexpected results like this, you need to breakdown
your expressions to see what is really be evaluated.

On Sat, Jul 30, 2011 at 1:48 AM, Tyler Rinker <tyler_rinker at
hotmail.com> wrote:>
> Greetings R Community,
>
> I am working with the ifelse function and it is returning something
unexpected. ?In the code the line with the MODE1 assignment the output is a
vector [1] 4 5 6 ?but when I put the MODE1 object into the ifelse function
[R}'s output for MODE1 is the first number from the string (4). ?Why is
this? ?Given the supplied vector of x I would assume both the MODE1 and ifelse()
lines to return the same result. ?I would like the ifelse to return the entire
vector [1] 4 5 6 as in the previous line.
>
> OS: Win7
> R version 2.14 beta
>
>
> #======================================================================>
# ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?Beginning of code
> #======================================================================>
x<-c(2,3,4,4,5,5,6,6,8,10)
>
> df<-as.data.frame(table(x))
> df<-df[order(df$Freq),]
> m<-max(df$Freq)
> (MODE1<-as.vector(as.numeric(as.character(subset(df,Freq==m)[,1]))))
> ifelse(sum(df$Freq)/length(df$Freq)==1,warning("No Mode: Frequency of
all values is 1", call. = FALSE),MODE1)
> #======================================================================>
# ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? End of code
> #======================================================================>
> ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?R Console Output
>> (MODE1<-as.vector(as.numeric(as.character(subset(df,Freq==m)[,1]))))
> [1] 4 5 6
>> ifelse(sum(df$Freq)/length(df$Freq)==1,warning("No Mode: Frequency
of all values is 1", call. = FALSE),MODE1)
> [1] 4
>
> Thank you in advance,
> Tyler
> ? ? ? ?[[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>


-- 
Jim Holtman
Data Munger Guru

What is the problem that you are trying to solve?

R. Michael Weylandt <michael.weylandt@gmail.com>

2011-Jul-30 05:59 UTC

head link

[R] ifelse returns

So the thing is this, ifelse puts together a vector elementwise from two
other vectors (or other things, but vectors is vague enough for now) based
on a series of T/F values: you only put in one logical test, so you only get
a vector of length 1 back, here MODE1[1]=4. It seems like a regular if/else
statement (not the vector function) would do the job here:

if (sum(df$Freq)/length(df$Freq)==1){
    warning("No Mode: Frequency of all values is 1", call. = FALSE)
} else {
    print(MODE1)
}

If for whatever reason you really don't want to use the if/else structure, I
suppose you could repeat your logical test three times e.g.,

test <- sum(df$Freq)/length(df$Freq)==1; test = rep(test,length(MODE1));
ifelse(test,warning("No Mode: Frequency of all values is 1", call.
FALSE),MODE1)

but don't do that: it's ridiculous.

Hope this works for you,

Michael Weylandt


On Sat, Jul 30, 2011 at 12:48 AM, Tyler Rinker
<tyler_rinker@hotmail.com>wrote:
>
> Greetings R Community,
>
> I am working with the ifelse function and it is returning something
> unexpected.  In the code the line with the MODE1 assignment the output is a
> vector [1] 4 5 6  but when I put the MODE1 object into the ifelse function
> [R}'s output for MODE1 is the first number from the string (4).  Why is
> this?  Given the supplied vector of x I would assume both the MODE1 and
> ifelse() lines to return the same result.  I would like the ifelse to
return
> the entire vector [1] 4 5 6 as in the previous line.
>
> OS: Win7
> R version 2.14 beta
>
>
> #======================================================================>
#                                        Beginning of code
> #======================================================================>
x<-c(2,3,4,4,5,5,6,6,8,10)
>
> df<-as.data.frame(table(x))
> df<-df[order(df$Freq),]
> m<-max(df$Freq)
> (MODE1<-as.vector(as.numeric(as.character(subset(df,Freq==m)[,1]))))
> ifelse(sum(df$Freq)/length(df$Freq)==1,warning("No Mode: Frequency of
all
> values is 1", call. = FALSE),MODE1)
> #======================================================================>
#                                             End of code
> #======================================================================>
>                                                R Console Output
> >
(MODE1<-as.vector(as.numeric(as.character(subset(df,Freq==m)[,1]))))
> [1] 4 5 6
> > ifelse(sum(df$Freq)/length(df$Freq)==1,warning("No Mode:
Frequency of all
> values is 1", call. = FALSE),MODE1)
> [1] 4
>
> Thank you in advance,
> Tyler
>        [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
	[[alternative HTML version deleted]]

Tyler Rinker

2011-Jul-30 06:38 UTC

head link

[R] ifelse returns

Thanks toy Jim and Michael for their response.  The suggestion to use regular
if/else was spot on.
 
> From: tyler_rinker@hotmail.com
> To: r-help@r-project.org
> Date: Sat, 30 Jul 2011 01:48:21 -0400
> Subject: [R] ifelse returns
> 
> 
> Greetings R Community,
> 
> I am working with the ifelse function and it is returning something
unexpected. In the code the line with the MODE1 assignment the output is a
vector [1] 4 5 6 but when I put the MODE1 object into the ifelse function
[R}'s output for MODE1 is the first number from the string (4). Why is this?
Given the supplied vector of x I would assume both the MODE1 and ifelse() lines
to return the same result. I would like the ifelse to return the entire vector
[1] 4 5 6 as in the previous line.
> 
> OS: Win7
> R version 2.14 beta
> 
> 
> #======================================================================>
# Beginning of code
> #======================================================================>
x<-c(2,3,4,4,5,5,6,6,8,10)
> 
> df<-as.data.frame(table(x)) 
> df<-df[order(df$Freq),] 
> m<-max(df$Freq) 
> (MODE1<-as.vector(as.numeric(as.character(subset(df,Freq==m)[,1]))))
> ifelse(sum(df$Freq)/length(df$Freq)==1,warning("No Mode: Frequency of
all values is 1", call. = FALSE),MODE1)
> #======================================================================>
# End of code
> #======================================================================>
> R Console Output
> >
(MODE1<-as.vector(as.numeric(as.character(subset(df,Freq==m)[,1]))))
> [1] 4 5 6
> > ifelse(sum(df$Freq)/length(df$Freq)==1,warning("No Mode:
Frequency of all values is 1", call. = FALSE),MODE1)
> [1] 4
> 
> Thank you in advance,
> Tyler 
> [[alternative HTML version deleted]]
> 
> ______________________________________________
> R-help@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code. 		 	   		  
	[[alternative HTML version deleted]]

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